Methods and apparatus toward preventing esc bonding adhesive erosion

ABSTRACT

Embodiments of the present invention provide chamber components having a protective element for shielding bonding material from processing environments in a processing environment. The protective element may include protective seals, protective structures, erosion resistive filers, or combinations thereof. Embodiments of the present invention reduce erosion of bonding material used in a processing chamber, thus, improving processing quality and reducing maintenance costs.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending U.S. patent applicationSer. No. 13/651,967, filed Oct. 15, 2012, and which claims benefit ofU.S. Provisional Patent Application Ser. No. 61/638,908, filed Apr. 26,2012, each of which is incorporated herein by reference,

BACKGROUND

1. Field of the Invention

Embodiments of the present invention relate to composite structuresjoined by bonding materials with enhancing thermal and/or chemicalstabilities. Particularly, embodiments of the present invention relateto an electrostatic chuck having two or more components joined by abonding material.

2. Description of the Related Art

Semiconductor processing chambers often include parts that are formed bybonding two or more components together with bonding materials toachieve desired properties. For example, electrostatic chucks, used forsupporting and securing substrates during processing, usually include adielectric puck bonded to a metallic base by a thermal conductivebonding material. The bonding materials provide secured connectionbetween different components while providing thermal conductivity and/orelectrical insulation. However, the bonding materials can have negativeimpact on processing, especially when the processes are performed atelevated temperatures or in a hash chemical environment. For example,when exposed to a plasma, a bonding material in an electrostatic chuckmay erode and generate particles causing particle contamination in theprocessing chamber.

Embodiments of the present invention provide apparatus and methods forpreventing bonding material erosion and particle generation.

SUMMARY

Embodiments of the present invention provide apparatus and methods forprotecting bonding material used in joining chamber components, such asan electrostatic chuck, from processing environments in a processingenvironment.

One embodiment of the present invention provides an apparatus for usingin a processing chamber. The apparatus includes a first component, asecond component and a bonding material joining the first component andthe second component. The apparatus further includes a protectiveelement for preventing the bonding material from erosion in theprocessing chamber.

Another embodiment of the present invention provides an electrostaticchuck for a processing chamber. The electrostatic chuck comprises achuck body having an upper surface configured to support a substratethereon and a lower surface opposing the upper surface, a chuck basehaving an upper surface facing the lower surface of the chuck body, anda bonding material joining the lower surface of the chuck body and theupper surface of the chuck base. The electrostatic chuck furtherincludes a protective element for preventing the bonding material fromerosion caused by environment in the processing chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments,

FIG. 1A is a sectional side view of an electrostatic chuck havingprotective seals according to one embodiment of the present invention.

FIG. 1B is an enlarged partial sectional view of the electrostatic chuckof FIG. 1A.

FIG. 1C is an enlarged partial sectional view of an electrostatic chuckaccording to another embodiment of the present invention.

FIG. 1D is an enlarged partial sectional view of an electrostatic chuckaccording to another embodiment of the present invention.

FIG. 1E is a top view of the electrostatic chuck of FIG. 1A with chuckbody removed.

FIG. 2A is a sectional side view of an electrostatic chuck having aprotective structure according to one embodiment of the presentinvention.

FIG. 2B is an enlarged partial sectional view of an electrostatic chuckhaving a protective structure according to another embodiment of thepresent invention.

FIG. 2C is an enlarged partial sectional view of an electrostatic chuckhaving a protective structure according to another embodiment of thepresent invention.

FIG. 3 is a sectional side view of a plasma processing chamber having anelectrostatic chuck according to embodiments of the present invention.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is also contemplated that elements and features oaf oneembodiment may be beneficially incorporated on other embodiments withoutfurther recitation,

DETAILED DESCRIPTION

Embodiments of the present invention provide apparatus and methods forprotecting bonding material used in joining chamber components, such asan electrostatic chuck, from processing environments in a processingenvironment. In one embodiment, a protective seal is disposed tosurround an edge of the bonding material from exposure to processingenvironment. In another embodiment, a protective structure is formedaround a bonding material in a chamber component to prevent directexposure of the bonding material to the processing environment.According to another embodiment of the present invention, a bondingmaterial comprising a silicon filler and a polymer adhesive base is usedin joining chamber components with reduced particle generation.Embodiments of the present invention reduce erosion of bonding materialused in a processing chamber, thus, improving processing quality andreducing maintenance costs.

FIG. 1A is a sectional side view of an electrostatic chuck 100 accordingto one embodiment of the present invention. The electrostatic chuck 100may be movably or fixedly positioned in a substrate processing chamberfor supporting a substrate during processing. The electrostatic chuck100 includes a chuck body 110 secured to a chuck base 120 by a bondingmaterial 130. A protective seal 140 is disposed around the bondingmaterial 130 to protect the bonding material 130 from a processingenvironment.

The chuck body 110 has a substantially planar upper surface 112 forsupporting a substrate 102 thereon. The chuck body 110 also has asubstantially planar lower surface 114 for receiving the bondingmaterial 130 and coupling to the chuck base 120. The chuck body 110 maybe formed from a dielectric material, in one embodiment, the chuck body110 may be formed from a ceramic, such as aluminum oxide. An electrode118 may be embedded in the chuck body 110. The electrode 118 may be athin metal plate or a metal mesh. The electrode 118 may be large enoughto encompass substantially the entire area of the substrate 102. Theelectrode 118 may be coupled to a power source, such as a DC voltagesource, to produce electrostatic chucking force to attract and securethe substrate 120 on the upper surface 112. Optionally, the electrode118 may also be coupled to a RF power source for generating capacitivelycoupled plasma in a processing chamber.

The chuck body 110 may have three or more through holes 116 to allowlift pins 104 passing through. The chuck body 110 may be shapedaccording to the shape of the substrate 102 being processed. Forexample, the chuck body 110 may be a circular disk for supporting acircular substrate, such as a semiconductor substrate. The chuck body110 may also be a rectangular plate for supporting rectangularsubstrates, such as glass substrates for forming liquid crystallinedisplay devices.

The chuck base 120 has an upper surface 122 for receiving the bondingmaterial 130 and the chuck body 110. The upper surface 122 may besubstantially planar. The chuck base 120 may be formed from a thermalconductive material, such as a metal, to provide temperature control tothe chuck body 110. In one embodiment, the chuck base 120 is formed fromaluminum. The chuck base 120 may have cooling channels 123 formedtherein. The cooling channels 123 may be connected to a cooling fluidsource (not shown) and have cooling fluid circulated therein. The chuckbase 120 may also have one or more heating elements 124 formed thereinfor providing heating to the chuck body 110. The one or more heatingelements 124 may form multiple heating zones to obtain desired heatingeffect. According to embodiments of the present application, the one ormore heating elements 124 may form four independently controlled heatingzones. The chuck base 120 may have lift pin openings 126 formedtherethrough and aligned with the through holes 116 in the chuck body110 for receiving lift pins 104. In one embodiment, casing elements 132,134, 138 may be disposed in the lift pin openings 126 for guiding thelift pins 104. The casing elements 132, 134, 138 may be formed from adielectric material, such as VESPEL® polymer or polyether ether ketone(PEEK), to provide electrical isolation between the lift pins 104 andthe chuck base 120.

The bonding material 130 is disposed between the lower surface 114 ofthe chuck body 110 and the upper surface 122 of the chuck base 120 tojoin the chuck body 110 and the chuck base 120 together. The bondingmaterial 130 may be in the form of a sheet shaped similar to the chuckbody 110 and the chuck base 120. In one embodiment, the sheet of bondingmaterial 130 may include three or more lift pin holes 136 correspondingto the through holes 116 for the lift pins 104. Alternatively, thebonding material 130 may be liquid based.

The bonding material 130 is configured to provide secure joint betweendissimilar materials, such as the ceramic chuck body 110 and themetallic chuck base 120. The bonding material 130 also provides thermalconduction between the joined components. In one embodiment, the bondingmaterial 130 may be a polymer based bonding adhesive with fillermaterials to provide thermal conductivity. The bonding material 130 maybe a polymer based bonding adhesive with erosion resistive fillers. Inone embodiment, the filler material includes silicon and the polymerbase material includes Silicone. The concentration of filler material insilicone base Is controlled to achieve a thermal conductivity of 1 W/mk.

Fillers in conventional bonding material may be eroded in an etchingchemistry, such as a processing environment including NF₃ or NF₃ and O₂,generating white particles and causing contamination. Compared tobonding materials with traditional fillers, the bonding material 130with silicone base and silicon filler does not causing particlecontamination in a processing chemistry including NF₂ or NF₃ and O₂,thus greatly reducing particle contamination. For example, in NF₃chemistry, the base polymer Silicone is attacked and the Siliconevolatilizes, leaving the traditional fillers, such as alumina (Al₂O₃)fillers, behind causing particle problems. When silicon fillers areused, both the silicon filler and the silicone base volatilize under theNF3 attack without generating any particles. The bonding material 130comprising silicon fillers may be used alone or in combination with theprotective seal 140.

In one embodiment, the protective seal 140 circum scribes the bondingmaterial 130 to prevent interaction between the bonding material 130 andthe processing environment. In one embodiment, a recess 144 may beformed between the chuck body 110 and the chuck base 120 to hold theprotective seal 140 in position. Optionally, a protective seal 142 maybe disposed around each lift pin holes 136 in the bonding material 130to prevent the bonding material 130 from being exposed to environment inthe lift pin holes 136.

The protective seals 140, 142 may be formed from materials maintain aseal between the chuck body 110 and the chuck base 120 when exposed tothe processing environment. The protective seals 140, 142 may be formedfrom an elastomer, such as a perfluoroelastomer. For operating in anetching chemistry including NF₃ or NF₃ and O₂, the protective seals 140,142 may be formed by one of but not limited to KALREZ® 8575perfluoroelastomer, DUPRA® 192 perfluoroelastomer, KALREZ® 8085perfluoroelastomer, CHEMRAZ® XPE elastomer. Other materials, such asL7505, SC513 (Chemraz 513), L8015r1 G758 (Perlast), L8010, are alsosuitable for protective seals. The protective seals 140, 142 may be inthe form of an O-ring, gasket, cup seal or have another suitableprofile. The protective seals 140, 142 may optionally be spring loaded.

As shown in FIG. 1B, the recess 144 in the electrostatic chuck 100 maybe defined by a step formed in the chuck base 120 and the lower surface114 of the chuck body 110. Since only the chuck base 120 is machined toform the recess 144, this configuration is simple to implement. FIG. 1Eis a top view of the chuck base 120 of the electrostatic chuck 100 withthe chuck body 110 removed with the protective seals 140, 142 visible.

Alternatively, a recess for the protective seal 140 may be formed inboth the chuck body 110 and the chuck base 120, or on the chuck body 110only.

FIG. 1C is an enlarged partial sectional view of an electrostatic chuck100C according to another embodiment of the present invention. Theelectrostatic chuck 100C is similar to the electrostatic chuck 100 ofFIG. 1A except that the protective seal 140 is secured in a recess 144Cdefined by a step 115C formed on the lower surface 114 of the chuck body110 and a step 128C formed on the upper surface 122 of the chuck base120. This configuration ensures that the bonding material 130 is coveredby a middle portion of the protective seal 140.

FIG. 1D is an enlarged partial sectional view of an electrostatic chuck1000 according to another embodiment of the present invention. Theelectrostatic chuck 100D is similar to the electrostatic chuck 100 ofFIG. 1A except that the protective seal 140 is secured in a recess 144Ddefined by a step 1150 formed on the lower surface 114 of the chuck body110 and the upper surface 122 of the chuck base 120. Only the chuck body110 is machined to form the recess 144 d.

In addition or alternative to using a protective seal to prevent erosionto bonding materials, embodiments of the present invention also provideelectrostatic chucks having shielding features within the chuck bodyand/or chuck base for protecting the bonding materials.

FIG. 2A is a sectional side view of an electrostatic chuck 200 having abonding material protective structure, i.e., a shielding feature,according to one embodiment of the present invention. The electrostaticchuck 200 may be movably or fixedly positioned in a substrate processingchamber for supporting a substrate during processing. Similar to theelectrostatic chuck 100, the electrostatic chuck 200 includes a chuckbody 210 secured to a chuck base 220 by a bonding material 230 that isthe same as the bonding material 130. A protective structure 216 may beformed in the chuck body 210 and/or the chuck base 220 to shield thebonding material 230 from a processing environment

The chuck body 210 has an upper surface 212 for supporting a substrate102 thereon and a substantially planar lower surface 214 for receivingthe bonding material 230. The chuck body 210 may be formed from adielectric material. An electrode 218 may be embedded in the chuck body210.

The chuck base 220 has an upper surface 222 for receiving the bondingmaterial 230 and the chuck body 210. The chuck base 220 may have coolingchannels 223 formed therein and heating elements 224 embedded thereinfor temperature control.

The bonding material 230 is disposed between the lower surface 214 ofthe chuck body 210 and the upper surface 222 of the chuck base 220 tojoin the chuck body 210 and the chuck base 220 together. The lowersurface 214 of the chuck body 210 and the upper surface 222 of the chuckbase 220 may be smaller than outer edges of the chuck body 210 and thechuck base 220 so that the bonding material 230 may be surrounded by theprotective structure 216 formed by the chuck body 210 and/or the chuckbase 220.

According to the embodiment shown in FIG. 2A, the chuck base 220 has astep 228 dropping down from the upper surface 222. The protectivestructure 216 is in the form of a lip that extends downward from thelower surface 214 of the chuck body 210. The lip may be continuous. Whenthe chuck body 210 is secured to the chuck base 220, the protectivestructure 216 in the form of a lip 216 extends above the step 228 andcovers the interface between the lower surface 214 of the chuck body 210and the upper surface of the chuck base 220, thus laterally surroundingthe bonding material 230 and shielding the bonding material 230 fromline of sight exposure to the environment within the chamber. Withoutusing a protective seal, the protective structure 216 of theelectrostatic chuck 200 eliminates the needs to maintain and replace theprotective seals, thus, reducing operation cost. In one embodiment, acontinuous hp 217 may also be formed around each lift pin passages 219to prevent the bonding material 230 from being exposed to the processingenvironment.

Even though the protective structure 216 is shown in FIG. 2A to be in aform of a lip from the chuck body 210, any suitable structures may beused to shield the bonding material 230. For example, FIG. 2B is anenlarged partial sectional view of an electrostatic chuck 200B having aprotective structure in the form of a protective lip 228B extendingupwardly from chuck base 220 and surrounding an outer edge 216B of thechuck body 210. In an electrostatic chuck 200C shown in FIG. 2C, thechuck base 220 has a groove 229 configured to receive a lip 215C fromthe chuck body 210. The groove 229 and the lip 215C form a maze toisolate the bonding material 230 from the processing environmentsurrounding the electrostatic chuck 2000.

According to embodiments of the present invention, one or moreprotective elements, such as protective seals, protective structures, orerosion resistive fillers may be used alone or in combination to preventbonding material from erosion in a processing environment.

Electrostatic chucks according to embodiments of the present inventionmay be used in various processing chambers, such as in plasma etchingchambers, chemical vapor deposition chambers, plasma enhanced depositionchambers, atomic layer deposition chambers, ion implantation chamber,for supporting substrates during processing.

FIG. 3 is a sectional side view of a plasma processing chamber 300having the electrostatic chuck 100 disposed therein. The electrostaticchuck 100 may be used to support a variety of substrates, such assemiconductor substrates and reticles, and accommodating a variety ofsubstrate sizes. Alternatively, any electrostatic chuck described abovemay he used in position of the electrostatic chuck 100.

The plasma processing chamber 300 includes a bottom 322, sidewalls 326and a chamber lid 343 disposed over the sidewalls 326 defining aprocessing volume 341. The plasma processing chamber 300 furtherincludes a liner 323 disposed in the processing volume 341 to preventthe sidewalls 326 from damage and contamination from the processingchemistry and/or processing by-products. A slit valve door opening 335is formed through the sidewall 326 and the liner 323 to allow passage ofthe substrates and substrate transfer mechanism. A slit valve door 324selectively open and close the slit valve door opening 335.

The electrostatic chuck 100 is disposed in the processing volume 341. Alift 327 is configured to raise and lower lift pins not shown) relativeto the electrostatic chuck 100 during processing and loading/unloadingthe substrate 102. The electrostatic chuck 100 may be coupled to a biaspower source 321 for generating chucking force to secure the substrate102 on the electrostatic chuck 100.

One or more processing gases may be supplied to the processing volume341 from a gas source 303 via an inlet 344. A vacuum pump 330 is fluidcommunication with the processing volume 341. The vacuum pump 330 may beused to pump the processing volume 341 and maintain a low pressureenvironment through a plenum 336.

The plasma processing chamber 300 includes an antenna assembly 370disposed outside the chamber lid 343. The antenna assembly 370 may be °Wed to a radio-frequency (RE) plasma power source 374 through a matchingnetwork 373. During processing, the antenna assembly 370 is energizedwith RE power provided by the power source 374 to ignite a plasma ofprocessing gases within the processing volume 341 and to maintain theplasma during processing of the substrate 102.

The plasma processing chamber 300 may be used for various plasmaprocesses. In one embodiment, the plasma processing chamber 300 may beused to perform drying etching with one or more etching agents. Forexample, the plasma processing chamber 300 may be used for ignition ofplasma from a precursor including C_(A)F_(y) (where x and y can bedifferent allowed combinations), O₂, NE₃, or combinations thereof.Embodiments of the present invention may also be used in etchingchromium for photomask applications, etching a profile, such as a deeptrench and through silicon vias (TSV) in a silicon substrate havingoxide and metal layers disposed on the substrate.

Even though electrostatic chucks joined by bonding materials aredescribed above, embodiments of the present invention may be used in anycomposite structures joined by bonding materials to protect the bondingmaterial from operating environment. For example, embodiments of thepresent invention may be applied to gas distribution showerheads havingtwo or more components joined by a bonding material.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

What is claimed is:
 1. An apparatus use in a processing chamber,comprising: a first component having a first surface; a second componenthaving a second surface, wherein the second surface faces the firstsurface of the first component; a bonding material disposed between thefirst surface and the second surface and joining the first component andthe second component; and a protective element disposed for preventingthe bonding material from erosion in the processing chamber, wherein theprotective element comprising a silicon filler disposed in the bondingmaterial.
 2. The apparatus of claim 1, further comprising a protectivesea surrounding the bonding material.
 3. The apparatus of claim 2,wherein the protective seal is disposed in a recess formed at aninterface between the first component and the second component.
 4. Theapparatus of claim 3, wherein the recess is defined by a step formed inan outer region of the first component, and the step facing the secondcomponent.
 5. The apparatus of claim 3, wherein the recess is defined bya first step formed in an outer region of the first component and asecond step formed in an outer region of the second component.
 6. Anapparatus for use in a processing chamber, comprising: a first componenthaving a first surface; a second component having a second surface,wherein the second surface faces the first surface of the firstcomponent; a bonding material disposed between the first surface and thesecond surface and joining the first component and the second component;a protective structure extending from the first surface if the firstcomponent covering the bonding material, the protective structureintegral with the first component.
 7. The apparatus of claim 6, whereinthe protective structure comprises a continuous Up extending from thefirst component and overlapping an interface between the first componentand the second component in which the bonding material is disposed. 8.The apparatus of claim wherein the protective structure furthercomprises a groove formed in the second component for receiving thecontinuous lip.